Pyrophyllite
>
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al₂Si₄O₁₀(OH)₂. It occurs in two forms: crystalline folia and compact masses; distinct crystals are not known. Wikipedia
Color: Brown green, brownish yellow, greenish, gray green, gray white
Mass: 360.31 g/mol
Birefringence: δ =0.0450–0.0620
Cleavage: Perfect
Crystal class: Prismatic (2/m); or pinacoidal (1)
Crystal habit: Compact spherulitic aggregates of needlelike radiating crystals; as fine grained foliated laminae, granular, massive
Crystal system: Monoclinic or triclinic
Show more
Show less